In the latest COVID-19 development, the Canberra Raiders, ACT Brumbies, Canberra Cavalry and Canberra United are set to be caught up in quarantine changes.

ACT Health is enforcing new restrictions in reaction to the growing cluster in Sydney, urging people to avoid travel to greater Sydney and enforcing quarantine for anyone arriving from Greater Sydney, Central Coast, Wollongong and Nepean Blue Mountains from Monday.

Sydney-based Raiders and Brumbies players were set to return home during their end-of-year break, while others would likely have travelled north to enjoy a rest from NRL and Super Rugby preparations.

But any players going to Sydney and its surrounding regions would need to spend two weeks in quarantine before restarting training.

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The Brumbies are due back for pre-season training in 14 days on January 4, with any players required forced to avoid travelling to Sydney and surrounding regions as of Monday. Wallabies squad members are not due back until mid-January.

The Raiders' senior players - barring State of Origin trio Josh Papalii, Jack Wighton and Dunamis Lui - will return to club headquarters for pre-season training on Monday before a short Christmas break.

The restrictions could be a major blow for the Canberra Cavalry's ABL campaign, days after border restrictions saw them withdraw from a season-opening series in Perth.

Six matches are in jeopardy with the Cavalry due to face the Sydney Blue Sox at Blacktown International Sportspark on December 28.

Canberra are scheduled to round out a series against Sydney at Narrabundah Ballpark from December 29-31, before returning for three more games in Blacktown in the new year. All six matches are balanced on a knife's edge.

Canberra United are slated to face Sydney FC in the W-League at Viking Park on January 3. It's unclear if the teams will be able to apply for an ACT government exemption to ensure those games go ahead.

United's season opener in Perth is already in doubt given border restrictions could keep Canberra's NSW-based players from entering WA without quarantine.

W-League head Greg O'Rourke is committed to seeing every game of the season go ahead.

"Where games are impacted by border closures, we will postpone those matches to be played at the earliest opportunity," O'Rourke said.

Some Sydney Thunder staff had gone home for a break with the intention of returning for the club's Big Bash League game at Manuka Oval on December 26.